Real‐time wave vector analys's with a charge coupled device

Abstract

Acoustic measurement in the wavenumber domain can contribute significantly to the understanding of turbulent boundary layer processes. Unfortunately, the complexity of the required instrumenration generally prohibits field measurements. Similar problems occur in the real‐time analysis of wave propagation in dispersive media. Previous work [G. Maidanik and D. W. Jorgensen, J. Acoust. Sec. Am. 42, 494–501 (1967)] has been limited to a narrow wavenumber range. In the present study, a charge coupled device (CCD) was adapted to allow spatial steering over an extended range of wavenumbers (25 to 125 m−1). A 16‐stage parallel input‐serial output CCD chip was selected to sample and then delay signals from an eight‐element accelerometer array. Variation of a master clock steered the wave vector analyzer over the spatial domain. Simulated beam patterns for equal, binomial, and Dolph‐Chebyshev amplitude shading were obtained. The method was illustrated by measuring the directionality of dispersive flexural waves in ...